The ability to inhibit corrosion, rust formation, oxidation and deterioration is a very significant property of lubricating compositions and functional fluids. The significance of such properties becomes increasingly important when the lubricant or functional fluid is used in connection with very expensive equipment under severe operating conditions. The significance of the ability to inhibit corrosion is further emphasized when the lubricant, such as a gear oil, is used in an environment such that it comes into contact with water under extreme temperature and pressure conditions. In the absence of a corrosion inhibitor with high performance characteristics the useful life of the machinery will be substantially reduced. Accordingly, many manufacturers of equipment requiring the use of functional fluids and lubricants require that such fluids and lubricants contain corrosion inhibitors. A number of tests have been devised in order to rate the corrosion inhibiting properties of lubricants and functional fluids when used under extreme conditions. Accordingly, there is a significant need for corrosion inhibitors which can be easily and economically manufactured and provided in lubricants and functional fluids in order to provide corrosion inhibiting properties.
U.S. Pat. No. 3,929,650 to King et al discloses a particulate dispersion of an alkali metal borate. The borate is prepared by contacting boric acid with an alkali metal carbonate overbased metal sulfonate within an oleophilic liquid reaction medium. The reactants are contacted at a temperature in the range of 20.degree.-200.degree. C. for a period of 0.5-7 hours with the molar ratio of the boric acid to the alkaline metal carbonate being in the range of from 1-3.
U.S. Pat. No. 3,595,790 to Norman et al discloses a number of different oil soluble highly basic metal salts of various organic acids. Salts of sulfonic acids, carboxylic acids and phosphorus acids are obtained by reacting such acids with an excess amount of a metal base in the presence of an acidic gas such as carbon dioxide and a promoter such as alcohol under substantially anhydrous conditions. The basic metal salts are indicated as being useful as additives in crankcase oils (oils of low viscosity compared to gear oils) in order to neutralize undesirable acid bodies formed in crankcase oils during engine operation.